Hydraulic fluid



United States Patent 3,259,583 HYDRAULIC FLUID Stanley R. Sprague, East Alton, Ill., and Richard G.

Cunningham, University Park, Pa., assignors to Shell Oil Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Dec. 18, 1962, Ser. No. 245,375

3 Claims. (Cl. 25275) This invention relates to improved power transmission fluids and lubricants. More particularly it relates to a new power transmission fluid which meets requirements for various types of transmission fluid such as Type A transmission fluids, transaxle fluid and rear axle fluid and is also applicable in various other mechanical equipment.

Rigorous requirements hav been set up to qualify fluids for this service. These include wide temperature stability at both high and low temperatures and a pour point of 40 F. maximum to insure proper pumpability and fluidity at low temperatures. The fluid must not have a detrimental elfect on parts with which it comes in contact, such as metal surfaces, e.g., copper and solid organic surfaces such as rubber, organic resins and the like. The fluid must possess excellent antifrictional and extreme pressure characteristics to afford proper lubrication of gears, clutch plates and other parts of automotive equipment. The fluid must not cause chattering, squawking, squealing or produce other noises caused by the stickslip phenomenon of clutch plates or other parts of these mechanisms. The fluid must be foam resistant, must not damage elastomer seals by swelling, shrinking or hardening them, it must not be effected by foreign matter or water contamination and should be miscible with various available transmission fluids.

Now, in accordance with the present invention, a multifunctional power transmission fluid is provided which meets the above requirements and which comprises of a major amount of a high viscosity index (SO-100 VI) mineral oil in the viscosity range of from about 45 to about 150 SUS at 100 F., preferably between 80 and 100 SUS at 100 F. and containing minor, but critical, amounts of an essential additive mixture which produces unexpected results other than are attributable to the individual additives, which combination of additives in mineral oil produces the effective and superior power transmission fluid of the present invention. The essential additives are: (1) a high basic oil-soluble polyvalent where X is oxygen, sulfur, or a methylene radical and R is a C alkyl radical such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, hexyl, octyl radical and (3) zinc salt of an unsaturated fatty acid having from 12 to 18 carbon atoms. The combination of these three additives unexpected results as for example none of these materials alone possess anti-frictional properties and yet in combination they are excellent friction inhibitors. Also alone these additives cause swelling and other damage to elastomer seals and clutch plate materials but in combination they provide excellent protection for such materials. Additionally these materials in combination function synergistically with respect to detergency, oxidation stability and the like. Also oxidation and dispersancy life of transmission fluids of this invention are improved far beyond the expectancy of the additive combination as described.

The oil-soluble basic polyvalent metal organic sulfonates, known as dispersants and detergents. By highly basic sulfonate is meant that the amount of neutralizing agent used as far in excess, namely, in the range of from 20 to 1000% and preferably between 40 and 800% in excess of that normally required to neutralize the acid to produce the normal salt.

The basic sulfonates can be derived from any suitable material and prepared by any of the well-known methods. Preferred materials for making sulfonates include liquid petroleum fractions, alkyl substituted aromatic compounds and alkyl substituted polar-containing aromatic compounds. Although various basic metal sulfonates are contemplated for use in compositions of this invention, the basic sulfonates of the metals of Group II of the Periodic Table having an atomic number of from 12 to 56 inclusive, are preferred, and especially the alkaline earth metals (Ca, Ba, Mg, or Sr) within that group of metals. Specific basic sulfonates which are useful in compositions of this invention include basic calcium, barium, magnesium and/ or strontium, petroleum sulfonates of oil-soluble petroleum sulfonic acid, tetratertiarybutyl-naphthalene sulfonates, diwaxbenzene sulfonate, stearyl benzene sulfonate, diwaxnaphthalene sulfonate, ditertiary amyl phenol sulfonate and mixtures thereof.

The second essential additive of the present invention which is represented by Formula I includes the (a) N,N- bis(dialkyl aminophenyl)methane and (b) N,N'-bis(dialkyl aminophenyl)ether or thioether. The compounds of 1(a) can be prepared by suitable means such as by reacting N,N'-dialkyl aniline in an acid medium and adding formaldehyde to the reaction at low temperature of below 40 C. and thereafter allowing the reaction to raise to 60150 C. for several hours after which the end product is recovered. In the reaction it is preferred that an excess of 40l00% of the amine be used. Thus, N,N- bis(dimethyl aminophenyl)methane (Ex. I) is prepared by adding 3 moles of N,N-dimethyl aniline and 1 mole of formaldehyde (10% solution) to hydrochloric acid at 6075 C. and the mixture heated for 1-2 hours after which the end product was recovered. Other examples include: N,N'-(diethyl aminophenyl)methane, N,N'-bis (dipropyl aminophenyl)methane, N,N-bis(dibutyl aminophenyl)methane, N,N'-bis(ditert.butyl amin0phenyl) methane, N,N'-bis(diamyl aminophenyl)methane, N,N- bis(dioctyl aminophenyl)methane. The ether or thioethers of I(b) include N,N'-bis(dimethyl aminophenyl) ether, N,N'-bis(diethyl aminophenyl)ether, N,N'-bis(dipropyl aminophenyl)ether, N,N-bis(ditert.butyl aminophenyl)ether, N,N'-bis(dioctyl aminophenyl)ether and their thioether derivatives. Preferred compounds are N,N'-bis(ditert.butyl phenyl)ether and N,N'-bis(ditert. butyl phenyl)methane.

The third essential additive of this invention is a zinc salt of a C unsaturated fatty acid such as zinc oleate, zinc linoleate, zinc n'cinoleate.

The zinc salt norm-ally added to oils as a thickening agent in compositions of the present invention imparts unexpected anti-friction and anti-wear properties as well as aid in improving the stability of the oil composition and helps protect the electromers and clutch plate facings of the transmission system.

3 The additive (1) is used in amounts of -15% preferably 6-12% by Weight, while additives (2) and (3) are each used in amounts of 0.11%, preferably 0.20.6% by weight.

The base oil is a high VI mineral oil in the viscosity 5 and preferably between 0.1% and 5%. range of 45 to 150 SUS at 100 F. It should be highly The following compositions illustrate the invention: refined and essentially free of naturally occurring sulfur composition Percent Wt and nitrogen-containing compounds as well as olefinic Basic Ca 'petroleum sulfonate (40% excess materials but rich in aromatics, namely the oil should conbase) tain 5-15 aromatic hydrocarbons, predominantly poly- 10 N g g ig zgf O 5 aromatics such as alkylated naphthalene and anthracene. Zinc Oleatc Mineral oil particularly useful are high 80-100 VI min- Mineral {MR} 3 '166T zg g eral oils having a viscosity of 80100 SUS at 100 F. or a balance spray base oil of 60 SUS at 100 F. or mixture thereof. composition If desired, minor amounts of secondary additives can 15 Basic Ca 'petroleum sulfonate (40% excess be used in conjunction with the three essential additives base) 10 among which are included sulfurized and/ or sulfurized- N fi gg gig $558 3 };5155555 0 5 phosphorized fatty oils and derivatives thereof such as Zinc oleate y the free fatty acids, e.g. sulfurized sperm oil, sulfurized Mineral Oil lbgd'jbblgiggh l lard oil, sulfurized tallow, sulfurized oleic acid, sulfurizedbalance phosphorizecl sperm oil. Also useful are organo sulfides, Composition such as alkyl, alkaryl, aralkylycycloalkylmonoor disulfide Basic Ca 'petroleum sulfonate (40% excess such as amyl, octyl, lauryl, stearyl, butylphenyl, benzyl, base) 10 cyclohexyl monoor disulfides, reaction products of "T phosphorus sulfide and monohydroxy alcohols, olefins, gizi ammophenynether terpenes and metal salts thereof, such as reaction prodsulfurized 5; n 2 uct of P S -tcrpene sold commercially by Monsanto as Mineral oil (MVI 66 65;;ibbl'iffggz Santolube 394C, the properties of which are: viscosity balance y at 210 F., 145 SUS; specific gravity, 103; phosphorus, Composition 4.75%;sulfur, 12.5%. Zinc or calcium or barium dialkyl Basic Ca petroleum sulfonate (40% excess dithiophosphates derived from alkanols such as methylisobase) 10 butylcarbinol, isobutyl alcohol, Z-rnethyl-l-butanol, 3- N Z 55;552 13 5 185 3 751 25 5 0 5 pentanol and mixtures thereof. Preferred are the zinc Zinc olgate dialkyldithiophosphates sold by Lubrizol as Lubrizol 1060 sulfurized 5551 2 and136thePrOPeYtlesOfwhlch are: Mineral oil (MVI 100 sus at 100 F.), essentially balance. Lubrizol 1060 Lubrizol1360 Composition E:

Basic Ca petroleum sulfonate (40% excess Phosphorus, percent, w 1g 6 o 40 base) 10 N,N'-bis(ditert.butyl aminophenyl)oxide 0.5 Sulfunzed sperm oil 2 Zinc oleate 0.5 Antifoarnmg agents such as silicone polymers, aryl phosphates e.g. di and tricresyl phosphates, alkyl phosphate, sq gfi ifi ggg esters, e.g. dimethylsilicone polymer, tributyl phosphate mm y Mme p0 ymer and phenolic antioxidants can be incorporated into compositions of the present invention, such as alkyl phenols, e.g. diand trialkyl phenols, for instance, 2,4-, 2,3- 3,4- 2,6- and 3,5-diamyl phenol 2,5-dimethyl-6-tert-butyl phenol, 2,4-ditert-butyl-6-methyl phenol; fatty acids of Mineral oil SUS F.), balance.

Compositions A-E met all physical and performance requirements for Type 2 VDrive, Type A, Suflix A and Type C transmission fluids, the requirements for each 50 being as follows:

AUTOMATIC TRANSMISSION FLUIDPHYSICAL AND PERFORMANCE PROPERTIES Property Type 2, V-Drive Type A, Suilix A Type C Viscosity at 210 F., S.S.U High-Temp. Properties Flash Point, F.

Thermal Stability Low-Temperature Properties Pour Point.

Oxidation Stability Bench Oxidation Test.

Anti-wear Rust and Corr on Friction Control Rubber Seal'Test 300 hr. at 275 F. in Powerglide.

-l0 F. max

Not required Pass CRO L-39 Powerglide.

Pass Cu strip Pass humidity No spec. to be met 040% vol. increase 49 minimum 320 minimum (a) 300 hr. at 275 F. in Powerglide (b) hr. in oven at 64,000 ep. max. vis. at -40 F.

in Brookficld viscometer. N 0t required Pass lab cycling test in Hydramatic transmission.

Pass Cu strip Pass ASTM D-665 Pass proving ground test at {GM (Squawk, slip, shift 05% 01. increase 45 minimum.

Not specified. 300 hr. at 325 F. in Powerglidc.

20 F. max.

15% vis. increase after hrs. at 300 F Pass power steering pump test 0.004% vane weight loss).

General requirement of no dis tress with any metal in transmission.

No spec. to be met.

15% vol. increase.

from 10 to 20 carbon atoms such as lauric, palmitic or stearic acids, viscosity index and pour point depressants such as oil-soluble nitrogen-free polymethacrylates e.g. copolymers of octyl and lauryl methacrylates available The Oxidation Composition: Test (Hr.) A 360 E 405 X (Mineral oil 1 Basic Ca petroleum sulfonate+0.5% N,N bis(ditertbutylamino phenyDether Y (Mineral oil+10% Basic Ca petroleum sulfonate+0.5% N,N' bis(diter-tbutylamino phenyl)ether+0.5% Tricresyl phosphate Z Mineral toil-+05% N,N' bis(ditertbutylamino phenyl)ether XX (Mineral oil-{40% Basic Ca petroleum sulfonate+0.-5%, 4,4 methylene bis(2,6 diterL-butyl phenyl) 192 1 Mineral oil:80 SUS at 100 F.

Compositions of the present invention are excellent power transmission fluids for various engines and industrial equipment which also possess excellent lubricating and cooling properties.

We claim as our invention:

1. A power transmission fluid consisting essentially of a major amount of mineral oil having a viscosity range of from about 45 to about 150 SUS at 100 F. and a viscosity index of 80- 100 and from about 5% to about of an oil solub'le basic alkaline earth metal petroleum sulfonate containing to 1000% excess base normally required to neutralize the petroleum sulfonic acid and from about 0.1% to about 1% each of zinc oleate and N,N'-bis(dia-lkyl aminophenyl)ether.

2. A power transmission fluid consisting essentially of a major amount of mineral oil having a viscosity range of from about 45 to about 150 SUS at 100 F. and a Viscosity index of 80-100 and from about 5% to about 15% of an oil-soluble basic calcium petroleum su lionate containing to 800% excess base normally required .to neutralize the petroleum sulfonic acid and from about 0.1% to about 1% each of zinc oleate and N,N-bis(diterL-butyl aminO pheny-Dether.

3. A power transmission fluid having the following formula:

Percent w t.

Oil-soluble basic calcium petroleum sulfonate containing 40% -to 800% excess base normally required to neutralize the petroleum sulfonic acid 10 N,N'-bi:s(ditert.-butyl .aminophenyl) ether 0.5 Zinc oilea-te 0.25 Su'lfurized sperm toil 2 Mineral oil having a viscosity range of from about .to about 150 SUS at 100 F. and. a viscosity index of 80-100, essentially balance.

References Cited by the Examiner UNITED STATES PATENTS 2,290,860 7/1942 Burk et al. 252402 XR 2,367,264 1/1945 Burk et a1. 252401 XR 2,710,842 6/1955 Heisig et .al 252- 3,017,361 1/1962 Morris et al 25275 XR ALBERT T. MEYERS, Primary Examiner.

JULIUS GREENWALD, Examiner.

R. D. LOVERING, Assistant Examiner. 

1. A POWER TRANSMISSION FLUID CONSISTING ESSENTIALLY OF A MAJOR AMOUNT OF MINERAL OIL HAVING A VISCOSITY RANGE OF FROM ABOUT 45 TO ABOUT 150 SUS AT 100*F. AND A VISCOSITY INDEX OF 80-100 AND FROM ABOUT 5% TO ABOUT 15% OF AN OIL-SOLUBLE BASIC ALKALINE EARTH METAL PETROLEUM SULFONATE CONTAINING 20% TO 1000% EXCESS BASE NORMALLY REQUIRED TO NEUTRALIZE THE PETROLEUM SULFONIC ACID AND FROM ABOUT 0.1% TO ABOUT 1% EACH OF ZINC OLEATE AND N,N''-BIS(DIALKYL AMINOPHENYL)ETHER. 